Rotary pump machine



June 1932- e. E. T. EI'YSTON ROTARY PUMP MACHINE 3 Sheets-Sheet 1 FiledDec. 21, 1928 QQQCQJQDT June 14, 1932. G. E. r. EYSTON ROTARY PUMPMACHINE June 14, 1932.

G. E. T. EYsTN ROTARY PUMP MACH INE Filed D90. 21, 1928 3 Sheets-Sheet 3rotor,

Patented June 14, 1932 entree STATES PATENT oer-ice GEORGE EDWARD THOMASEYS TON,

OF'LONDON, ENGLAND, ASSIGNOR T0 POWERPLUS (1927) LIMITED, OF LONDON,ENGLAND, A CORPORATION OF GREAT BRITAIN ROTARY PUMP MACHINE Applicationfiled December 21, 1928, Serial No. 327,588, and in Great BritainDecember 23, 1927.

This invention comprises improvements in and connected with rotary pumpmachines and is concerned with that type of machine which comprises apiston body or rotor fitted with vanes or blades and eccentricallymounted in an outer casing so as to form a crescentshaped workingchamber through which the vanes move in pumping fluid from an inlet toan outlet of the pump casing. In this type 1 of machine, termedcrescent-chamber type the piston vanes are mounted in longitudinal slotsor recesses in the rotor and they may have a relative sliding movementin the slots or recesses as they sweep round in the casing or themovement may be of sliding-rocking :1 erned as to their position orotherwise.

The present invention has for its principal object to provide, inmachines of this type, an improved form of bearing for the blades in therecesses or slots of the piston body or this bearing enabling vanes orblades of light construction to be employed while minimiz'ng frictionlosses in the operation of these machines. It will be realized that itis of advantage to have blades of light con- 9'; struction as therebycentrifugal stresses and re-action forces are brought within low limits,and friction may be reduced, and reduction in friction losses leads togreater efficiency.

According to this invention the sides of the recesses or slots of therotor are recessed or cutaway in such manner that the vanes or bladeshave arunning clearance therein over part of their length, while overthe remainder of the length of the blades the sides of tl e recesses orslots present projecting and rigid bearing surfaces for the vanes orblades. The invention thus provides a simple manner of decreasing orsubdividing the bearing for thin fiat blades and there are no loosebearing parts to be fitted or become deranged or to increase the expenseof manufacture of the machines. Lubricant would be supplied only to thebearing surfaces and as theselie close against the blade, the lubricantsupply ports will always be covered by the blade and waste of lubricantor undue escape thereof to the.

working chamber of the machine will be pre-. In machines with shortblades the vented. bearing may be at one place central of the length ofthe blade and in cases Where the blades are longer, the bearing surfacesare suitably distributed along the recesses or slots at appropriatedistances apart in the length of the blade. In any case, the bearing isat only one place or at separated places and not over the whole of thelength of the: blade so that friction may be minimized. Approprlateformation or disposition of the bearing surfaces will still enableblades or vanes of plane, and thus light, construction 7 I to beemployed while lubrication also is advantageously efi'ected because itis only necessary to supply lubricant to the constricted or narrowedplaces where the vanes bear in the recesses or slots. Lubricant can besupplied much more efliciently and simply to localized points than overthe whole length of a vane or blade. As Will be realized, the sides ofrotor slots or recesses of the nature indicated will have a sort ofcastellated form in transverse section. The actual bearing parts may beadvantageously fitted with anti-friction or hearing liners or surfaces.

The vanes may lie in planes radiating from the central axis of thecasing of the machine or from the central axis of the rotor. In theformer case, the blades would have a sliding-rocking movement relativeto the rotor and oscillatory bearing or trunnion blocks would preferablybe provided for them in the slots of the piston body or rotor, the slotsof these blocks being of the castellated nature referred to. hen con-.structions are adopted in which the vanes or blades lie in planesradiating from the central axis of the piston body or rotor, the slotsin the rotor itself may be given the castellated form, though obviouslybearing members or blocks with castellated blade slots may be usedmounted fixedly in the slots of the rotor.

Asa modified form of construction, instead of forming the rotor slotswith castellations to provide bearing surfaces of the inner extent ofthe cut-outs e.

nature referred to, the thin blades may be formed in this manner and therotor slots be of equal width throughout their length, the blades insuch a construction thus comprising parts which form bearing surfaces atpoint or points along their length, while the remainder of the blades ismachined out slightly so that their surfaces over these parts have arunning clearance in their slots.

In order to enable ready understanding of the invention to be obtained,suitable e:\' amples of construction will now be described with the aidof the accompanying drawings, wherein Figure l is a perspective view ofa solid form of piston body or rotor for a machine of the type referredto, part being broken away to show the form of the bearing surfaces inthe rotor slots and a vane or blade being shown in one of the slots forpurposes of illustration.

Figure 1 is a cross-sectional view of a machine embodying the rotor andvane construction of Figure 1.

Figure :2 is a similar view of F .igure 1 of a modified construction butwith the rotor also broken away at the near end and with all of theslots fitted with vanes or blades.

Figure 8 illustrates another example with part broken away to facilitateunderstanding of the construction.

Figures l and 5 are diagrams to aid in un' derstanding the castellatednature of the bearing surface construction provided in accordance withthese improvements.

Figure 6 is a fragmentary view illustrating a modification of thetrunnion blocks for construction such as are seen in Figure 3.

Figure 7 is an elevation of a further modified form of trunnion orbearing block.

Figure 8 is a section on the VIIIVHI of Figure 7 and Figure 9 is a planView of a trunnion block and blade comprising a further modified form ofbearing surfaces for the blades of machines of the type referred to.

In Figure 1, the solid rotor body a is intended for fixed mounting on adriven shaft a Figure 1 which passes through the central bore Z) and ismounted eccentrically in an outer casing a having the usual inlet andoutlet connections as at M. As seen in these Figures, the rotor has sixslots 0 in which the vanes or blades, such as (Z, have relative slidingmovement in the well-known manner as the rotor revolves. Thesides of theslots over a greater part of their length are cut away as at so as toprovide a running clearance over a large part of the surface of theblade. As will be seen at the upper part of Fig are l, the bearingsurface parts f are practically entirely at the end parts of the slots.The section at 1 in Figure l is taken centrally of the length of therotor (Figure l) to show the It is not essenline tial, of course, thatthe cut-away parts 6 should have the semi-circular contour shown. Thisis only for convenience and economy in manufacture, for if desired thecut away parts could extend rectangularly as indicated, say, by thedotand dash lines at g in. Figure 1. It will be obvious, however, thatthe semi-circular form is the easiest to produce as it may be made by amilling cutter working in from the outer ends of the slots, the cutterbeing slightly wider than the slots to give the desired clearance to thecentral part of the blade on each face. The form of the outer end of theslots and the increase of width at the parts e is plainly seen at thelower forward side of Figure 1. The proportionate trans verse dimensionsor width of the slots at the parts 6 and f is slightly exaggerated forsake of illustration in Figures 1 and 1 and a si1nilar considerationapplies to other figures. In practice the width of the slots at 6 wouldonly be a fraction of a millimetre greater than at 7 (say :2 mm. wide ate and 1 mm. wide at f) so that the blades merely have arunning clearanceat 6. At the relatively projecting parts 7 they have a bearing fit inthe slots and it will be seen that as the bearing parts of the slots arelocalized practically at the ends of the slots, friction in the workingof the blades is considerably reduced as compared with what it would beif the blades had a bearing over the whole length of the slots. Theresultant improvement in the working of the blades will be readilyunderstood and a further advantage is that lubrication is simplifiedbecause oil need only be supplied to the parts f instead of along thewhole length of the slots. The section at 2 in Figure l is at one end ofthe rotor a and shows a suitable lubricating duct 7 in the rotor fed bythe duct 7' from a central duct in the rotor drive shaft a It will beseen that the duct f is situated near to the circumference of the rotor.In this way, better control of the lubricant supply is obtainablebecause the outlets from the lubricant supply ducts f are always coveredby the blades so that waste of lubricant and undue escape thereof to theworking space of the machine are prevented.

In the construction shown in Figure 2, the rotor or piston-body a is ofhollow cylindrical form with spaced slots around its periphery. Theblades (Z, as before have a relative sliding movement in these slots butthe bearing proper is taken in slots h in bearing blocks is mountedfixedly in recesses in the rotor. In this construction the bearingsurface in the slots is provided not by cutting away the sides of theslots as in Figure 1 but by cutting away the blades on each face atdifferent places along their length as shown at Z. The slots h are,therefore, of the same width throughout their length. Nevertheless, thebearing of the blades in the slots is only at separated points where theblades have not been cut away at m. This construction, therefore,provides similar advantages to the construction shown in Figure 1, andthe parts Z are as easily machined as the parts 6 in Figure 1, becauseit is readily possible to operate on the outside surfaces of the blades.

Figure 3 shows a similar blade and slot construction to that seen inFigure 2, but whereas in the previous figure (and also in Figure 1), theblades d have been centred in the rotor, in Figure 3 they are intendedto lie in planes radiating from the centre of the outer casing of themachine. It will be well understood that with this blade disposition,the movement of the blades relative to the rotor is not a pure slidingmovement but a slidingrocking movement and, therefore the bearing blocks76, with the slots h for the blades, are mounted in their recesses inthe rotor so that they may partake of an oscillatory movement as theblades rock, the rotor being cut away in the usual manner at n, to allowthe rocking movement. The reference letters applied to the blades andslots in Figure 3 are the same as those in Figure 2.

The diagrams, Figures 4; and 5, are respec tively cross-sectional viewsof the contiguous bearing surfaces in Figure l and Figures 2 and 3. Theyare purely fragmentary views and are intended to show the castellatednature of the slot or vane surfaces in cross-section and the nature ofthe clearances. Only one side of the vanes and slots is shown and theparts are indicated by the same reference letters as in Figures 1 to 3.

According to the modification illustrated by Figure 6, short recesses 0are provided in the slots of the bearing or trunnion blocks in theregion of the bearing surfaces at m to facilitate access ofoil to thebearing between the parts m and the side walls of the slots it. Theserecesses would face the interior of the rotor from which oil would gainaccess to the recesses by way of the cutouts at n in the case of Figure3, or through the slot parts 01/ Figure 2, which need only be rough outsince the bearing proper for the blades is in the slots h of the bearingblocks 70 as stated.

The cross-sectional form and the disposition of the recesses 0 are seenagain in Figures 7 and 8. These figures illustrate a suitable form whichmay be given to the hearing or trunnion blocks of constructions such asare shown in Figure 3, for the purpose of imparting lightness to theblocks. As will be seen in Figures 7 and 8, the blocks are bored orrecessed on either side at numerous points along their length as at pand this considerably lightens the blocks without detracting from thestrength required in them. Where the recesses 0 are situated ports 1"may lead from the bottoms of the adjacent recesses 10 to the slots 72.to allow further supply of lubricant by way of these recesses to theplaces where the blades take bearing in the slots.

The recesses in the blocks for lightening purposes, may of course, beformed in other ways, for example, by cutting away the block on oppositesides (top and bottom) between the bearing places so as to give it theform of short cylindrical parts joined by relatively narrow horizontalwebs. Lightened forms of block of this nature may also be used inconstructions such as are shown in Figure 2.

In the constructions so far described, the blades have beensubstantially plane or flat. This is one of the advantages of thisinvention, a sub-divided bearing surface being provided and yet theblades being of lightest possible form. If necessary, however, forinstance in high speed machines, reinforcing ribs may be fittedacrossthe blades, as shown by way of example at s in Figure 9. The blade inthis figure is of the form shown in Figures 2 and 3 and takes bearing inthe slots only at the parts m, the parts cut away at Z having a runningclearance in the slot h which is of the'same width throughout itslength, except where the ribs 8 are situated where there areenlargements t. The latter are so formed that the ribs do not take anybearing in the slots but have a running clearance, the bearing beingonlyover the parts m of the blade as stated. The bearing is at three placesalong the length of the blade, instead of at only two in Figures 2 and3, but obviously the number of bearing-places may vary according forexample, to the length of the machine. Ribs s of similar nature to thereinforcing ribs 8 just described are also seen applied to one of thevanes d in Figure 1, so as to indicate that such ribs are applicable toall constructions of machines made ac cording to the invention. I

In any of the constructions, the slots of the rotor or the hearing ortrunnion blocks may be fitted with anti-friction or bearing liners ofwhite metal or other suitable material, where the blades take thebearing in the slots.

As the invention is not concerned with means for controlling therelative'movements of the blades, no devices have been shown for thispurpose in the drawings. Obviously, however, the blades may be providedwith feet or projections or slotted to form feet at the inner edge forengaging in grooves. of centric rings mounted anti-frictionally in theouter casing of the machine, or they may be fitted into rings or membersrevoluble anti-frictionally about a centric and fixed shaft in thecasing of the machine all as will be understood without illustration bythose acquainted with the art. In constructions where trunnion blocksare used, as in Figure 3, provision may be made for governing orcontrolling the position of the trunnion blocks to keep the slots inmost favourable position with respect to the blades.

Lubrication of the bearing surfaces'niay be effected in any suitablemanner. In conits II l

nection with Figure 1 ducts f in the rotor have been described fordirectly leading lubricant to the bearing surfaces 7, while inconnection with Figure 6, mention has been made of the use of recesses oin the bearing or trunnion blocks is for facilitating lubrication ofthese parts indirectly by oil from the interior of the rotor. Otherexpedients may be adopted however, and as an example direct lubricationmay be eflected by leading oil through passages in the bearing ortrunnion blocks to the bearing places.

What I claim is:

1. A rotary pump machine comprising an outer casing, a piston body orrotor mounted eccentrically in said casing and having longitudinal slotsor recesses with side walls Which are recessed or cut away slightly atparts of their length to provide rigid flat projecting parts andslightly sunken clearance parts eX- tending to the outer edges of theslots, and relatively slidable piston vanes fitted in said slots orrecesses and adapted to take bearing on said rigid flat projecting partsover part of their length While having just a slight clearance, at saidclearance parts, over the remainder of their length.

2. A rotary pump machine comprising an outer casing, a piston body orrotor mounted eccentrically in said casing and having longitudinal slotsor recesses with side walls which are recessed or cut awaypart-circularly from the outside of the rotor in a manner to providerigid flat projecting parts on either side of sunken clearance parts,and relatively slidable piston vanes fitted in said slots or recessesand adapted to take bearing on said rigid flat projecting parts over thepart of their area while having just a slight clearance, at saidclearance parts, over the remainder of their area.

3. In a rotary pump machine of crescentchamber type, a piston body and apiston vane in the form of a thin blade having relative sliding movementin saidpiston body, the contiguous engaging surfaces of these partscomprising one or more rigid bearing projections formed on and ofshorter length than one of the parts and surfaces lying in a commonplane or planes on the other part, and reinforcing ribs on said pistonvane having a slight clearance in said piston body.

4. In a rotary pump machine of the crescent chamber type, a piston bodywith a relatively fixed longitudinal slot and a piston vane havingrelative sliding movement in said slot, contiguous opposed surfaces ofthe vane and slot parts being on one of these parts a plane surface andcomprising on the other part a rigid projection adapted to bear on saidplane surface, and the piston body having a lubricant duct leadingdirectly to an outlet in said slot in the space opposite saidprojection.

GEORGE EDWARD THOMAS EYSTON.

